The entirety of the East Wing of the White House will be demolished within days, two Trump administration officials have said.
Construction crews began demolishing parts of the structure on Monday, and the structure will be completely torn down by the weekend, the officials told the BBC's US news partner CBS.
It marks a significant expansion of a construction project announced by President Donald Trump over the summer. He previously said his $250m (£186m) White House ballroom addition would not interfere with the current building.
The White House has served as the historic home of the US president for two centuries. The East Wing was constructed in 1902 and was last modified in 1942.
Trump announced the construction had begun in a social media post on Monday, saying ground has been broken on the much-needed ballroom space.
For more than 150 years, every President has dreamt about having a Ballroom at the White House to accommodate people for grand parties, State Visits, etc, he wrote.
He said that the East Wing was completely separate from the White House, although it is attached to the main structure.
The Trump administration officials told CBS it was always the case that the East Wing would have to be modernised to enhance security and technology, but that during the planning process, it became apparent that the best option would be to demolish the entirety of the East Wing.
Trump has called the construction music to my ears.
You probably hear the beautiful sound of construction in the back... When I hear that sound, it reminds me of money, he told senators from his Republican Party at the White House on Tuesday.
His comments came after the National Trust for Historic Preservation, a Washington non-profit organisation that protects historic US sites, wrote a letter to White House officials saying it was deeply concerned by the project.
The trust asked Trump to pause demolition work, arguing that the White House was a national historic landmark and that officials needed to hold a public review process of the plan for the ballroom.
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